muse-song-convert: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/muse-song-convert - from package: muse

You may install the required package with command apt-get install {package}

Error in other languages:
muse-song-convert: bevel nie gevind nie
muse-song-convert: comandă negăsită
muse-song-convert: comando não encontrado
muse-song-convert: commande introuvable
muse-song-convert: command not found
muse-song-convert: käsku ei ole
muse-song-convert: không tìm thấy lệnh
muse-song-convert: komanda nerasta
muse-song-convert: Kommando nicht gefunden.
muse-song-convert: kommandot finns inte
muse-song-convert: komut yok
muse-song-convert: nie znaleziono polecenia
muse-song-convert: níor aimsíodh an t-ordú
muse-song-convert: no se encontró la orden
muse-song-convert: no s'ha trobat l'ordre
muse-song-convert: opdracht niet gevonden
muse-song-convert: parancs nem található
muse-song-convert: perintah tidak ditemukan
muse-song-convert: príkaz nenájdený
muse-song-convert: příkaz nenalezen
muse-song-convert: команда не найдена
muse-song-convert: командата не е открита
muse-song-convert: 命令找不到
muse-song-convert: コマンドが見つかりません